diff --git a/jcstest.c b/jcstest.c
index 98f16da6..358ed251 100644
--- a/jcstest.c
+++ b/jcstest.c
@@ -78,7 +78,7 @@ int main(void)
   jerr.pub.output_message = my_output_message;
 
   if(setjmp(jerr.jb)) {
-    // this will execute if libjpeg has an error
+    /* this will execute if libjpeg has an error */
     jcs_valid = 0;
     goto done;
   }
@@ -105,7 +105,7 @@ int main(void)
   #endif
 
   if(setjmp(jerr.jb)) {
-    // this will execute if libjpeg has an error
+    /* this will execute if libjpeg has an error */
     jcs_alpha_valid = 0;
     goto done2;
   }
diff --git a/turbojpeg.c b/turbojpeg.c
index 8689992a..c78402fa 100644
--- a/turbojpeg.c
+++ b/turbojpeg.c
@@ -519,9 +519,9 @@ DLLEXPORT unsigned long DLLCALL tjBufSize(int width, int height,
 	if(width<1 || height<1 || jpegSubsamp<0 || jpegSubsamp>=NUMSUBOPT)
 		_throw("tjBufSize(): Invalid argument");
 
-	// This allows for rare corner cases in which a JPEG image can actually be
-	// larger than the uncompressed input (we wouldn't mention it if it hadn't
-	// happened before.)
+	/* This allows for rare corner cases in which a JPEG image can actually be
+	   larger than the uncompressed input (we wouldn't mention it if it hadn't
+	   happened before.) */
 	mcuw=tjMCUWidth[jpegSubsamp];
 	mcuh=tjMCUHeight[jpegSubsamp];
 	chromasf=jpegSubsamp==TJSAMP_GRAY? 0: 4*64/(mcuw*mcuh);
@@ -538,9 +538,9 @@ DLLEXPORT unsigned long DLLCALL TJBUFSIZE(int width, int height)
 	if(width<1 || height<1)
 		_throw("TJBUFSIZE(): Invalid argument");
 
-	// This allows for rare corner cases in which a JPEG image can actually be
-	// larger than the uncompressed input (we wouldn't mention it if it hadn't
-	// happened before.)
+	/* This allows for rare corner cases in which a JPEG image can actually be
+	   larger than the uncompressed input (we wouldn't mention it if it hadn't
+	   happened before.) */
 	retval=PAD(width, 16) * PAD(height, 16) * 6 + 2048;
 
 	bailout: